1. Technical Field
The present invention relates to electrophotographic printing systems in general, and, in particular, to an apparatus for improving image fidelity on a high-speed electrophotographic printing system.
2. Description of Related Art
Within a conventional electrophotographic continuous form printing system, a photosensitive drum is electrically charged by a charger while receiving a laser light beam, and each character written on the photosensitive drum in the form of a latent image is developed by a developer. As a strip of printing paper is being delivered through the printing system, the developed toner images on the photosensitive drum are transferred onto the printing paper. After the fixing operation has been completed, the printing paper is received in a stacker.
Sometimes, the print quality may be degraded during printing. Specifically, when the developed toner images are fixed onto the printing paper with the aid of a preheating plate and a heat roll in the electrophotographic printing unit, the printing paper is thermally damaged to a certain extent, causing it to be warped due to local expansion and contraction of the printing paper. In addition, when the developed toner images are transferred onto the printing paper from a photosensitive drum, a portion of the developed toner images will probably be incorrectly transferred onto the printing paper because of the above-mentioned warpage of the printing paper. As a result, a portion of the developed toner images representing certain characters is not printed on the printing paper.
Consequently, it would be desirable to provide an apparatus for improving image fidelity on a high-speed electrophotographic continuous form printing system.